2 because that’s correct I I I I I I I I I I I I I I I I I I I
The answer is A.number of protons in the nucleus.
A baseball would hit the bat harder. This is because the baseball is a lot heavier and more dense than the plastic ball. The keyword that you're looking for is density. The baseball is dense.
Explanation:
It is given that,
A particle starts from rest and has an acceleration function as :

(a) Since, 
v = velocity




(b) 
x = position



(c) Velocity function is given by :


t = 1 seconds
So, at t = 1 second the velocity of the particle is zero.
we know that center of mass is given as
r = (m₁
+ m₂
)/(m₁ + m₂)
taking derivative both side relative to "t"
dr/dt = (m₁ d
/dt + m₂ d
/dt)/(m₁ + m₂)
v = (m₁
+ m₂
)/(m₁ + m₂)
taking derivative again relative to "t" both side
dv/dt = (m₁ d
/dt + m₂ d
/dt)/(m₁ + m₂)
a= (m₁
+ m₂
)/(m₁ + m₂)